The sale of 428,000 square feet to Arboretum Acquisitions LLC was for about $10 million, according to a real estate source.

Bingham Farms-based Core Partners LLC handled the leasing and management of the four buildings prior to the sale. Bingham Farms-based Burton-Katzman LLC owned the buildings.

Friedman will take over leasing, management and construction operations for four of the five buildings at the complex, located on 12 Mile Road between Farmington and Drake roads, according to Robert Gagniuk, associate of brokerage services for Friedman.

Kojaian will not have any role in leasing, management or construction, Gagniuk said. Kojaian is a silent partner in the deal, Gagniuk said.

Improvements are planned on the buildings' exteriors, landscaping and lobbies.

The buildings are 26 percent occupied, according a marketing brochure by Jones Lang Lasalle, which represented Burton-Katzman.

According to Washington, D.C.-based real estate information service CoStar Group Inc., the four buildings have the following individual occupancy rates:

• Arboretum I (115,000 square feet): 33 percent leased

• Arboretum II (129,000 square feet): 53 percent leased

• Arboretum III: (163,000 square feet): vacant

• Arboretum R: (20,000 square feet): vacant

Key tenants at the Arboretum are Grand Rapids-based Priority Health, Liberty Mutual and Logicalis Inc., according to the marketing brochure.

Priority Health, however, is moving from the complex in mid-May to 20,000 square feet of the 527,000-square-foot American Center office building northwest of the intersection of Franklin and West 11 Mile roads in Southfield.

Leasing and management at the 114,000-square-foot Arboretum IV building, which was not included in the sale, is handled by Southfield-based Signature Associates Inc., Gagniuk said. That building is 69 percent leased, according to CoStar. The Arboretum had an average occupancy rate of 94 percent from 2007 to 2012. However, the complex has struggled in the last year and a half. Trinity Health had been a key tenant but consolidated its 1,600 employees from the Arboretum and the Cabot Building at 27870 Cabot Drive in Novi into 340,000 square feet at the Victor Corporate Center in Livonia in October 2012.

More recently, a deal for Southfield-based auto supplier Federal-Mogul Corp. to lease 180,000 square feet of space in the Arboretum collapsed in the last two months. Federal-Mogul announced in January that it would put its 700 employees in the same amount of space in the 700,000-square-foot former Blue Cross Blue Shield of Michigan headquarters in Southfield.

Friedman also manages North Troy Corporate Park. The company is also part of the 1.2 million-square-foot complex's investment group, of which the majority owner is Miami-based Rialto Capital Management LLC. It was purchased in 2012 for $15.5 million, according to CoStar.

In June 2012, Crain's reported the occupancy rate was 24 percent. The current occupancy rate is between 42 percent and 50 percent, Gagniuk said.

"Like we achieved with North Troy Corporate Park, we will transform Arboretum Office Park into one of the most appealing options for companies seeking a modern office environment in the Farmington Hills area," David Friedman, president and CEO of Friedman Integrated Real Estate Solutions, said in a news release.